21531502242 has 32 divisors (see below), whose sum is σ = 47874772800. Its totient is φ = 7173118944.

The previous prime is 21531502207. The next prime is 21531502247. The reversal of 21531502242 is 24220513512.

21531502242 is a `hidden beast` number, since 2 + 153 + 1 + 502 + 2 + 4 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21531502247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15067 + ... + 208062.

It is an arithmetic number, because the mean of its divisors is an integer number (1496086650).

Almost surely, 2^21531502242 is an apocalyptic number.

21531502242 is an abundant number, since it is smaller than the sum of its proper divisors (26343270558).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21531502242 is a wasteful number, since it uses less digits than its factorization.

21531502242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224927 (or 224921 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The spelling of 21531502242 in words is "twenty-one billion, five hundred thirty-one million, five hundred two thousand, two hundred forty-two".